Question

In electromagnetic waves travelling in vacuum
(i) The electric field $ E $ is always perpendicular to the magnetic field $ B $
(ii) The cross product $ E \times B $ always gives the direction in which the waves travel.
(iii) The field $ E $ and $ B $ vary sinusoidally
(iv) There is a phase difference of $ \frac{\pi}{2} $ between $ E $ and $ B $
The correct statement (s) is (are)

• A. (i), (iii)
• B. (i), (iii), (iv)
• C. (i), (ii), (iii), (iv)
• D. (i), (ii), (iii)

Answer 1

Answer: (D)

Electromagnetic wave is a wave in which electric field vector and magnetic field vector are perpendicular to each other and also they are in same phase
$E \times B$ always give the direction in which wave travel. The direction of $E\times B$ is also perpendicular to both $E$ and $B$